The Audi RS5 and Mercedes C63 AMG Coupe are pretty impressive, but there's an obvious question - which one is faster?

To answer that, Tiff Needell took the coupes to Cadwell Park and tested them back to back. While we won't ruin the ending, both vehicles are pretty evenly matched on paper as the RS5 has 450 PS (331 kW / 444 hp) and the C63 has 457 PS (336 kW / 451 hp). Does the added weight of all-wheel drive hamper the RS5? You'll have to watch to find out.